Liner Seals

[Parzival]

If you are doing this kind of work you MUST have some accurate measuring tools. A micrometer and a large vernier caliper at a minimum along with a set of feeler gauges and a straightedge. The liners can be moved but you should move the pistons too. That means taking the pistons off the con rods. That means special tools. Something is very wrong if you get such a large difference in measurement side-to-side on one liner.

Something was wrong, the liner was leaning over toward the outside (away from the valley) of the engine. Making it high on the valley side, and low on the other. I took it back out and discarded that paper shim, and put it back toghether more carefully with a new one. This design just seems so... flimsy? Like how are these little paper rings supposed to seal the water jacket up!? I'm so nervous I'm almost crippled in anxiety over moving forward. I guess I'll just keep measuring, but I know I'm getting at least .16 of protrusion above the block, the .18 feeler gage fits under the straight edge . It says the minimum is .16 so I should be safe right? as in the clamping force should be great on the liners, and there is some room for error in that the paper will crush down, and so will the fire rings in the head gaskets....
Man this stuff can really keep you up at night.

[Jason]

When I rebuilt my engine, the advice I got from DPI was...

I notice you only sent yellow liner seals, so I assume I'm supposed to just use those instead of measuring the liner protrusion. Do I still still need to step the protrusion differences from cylinder to cylinder as described in the service manual or can I skip measuring all together?

-no need to measure. Just install the yellow seals on all cylinders. Follow the guidelines in the manual for tab orientation on the seals.

Though this was with new liners from DPI. I don't know if that makes any difference.

[Delorean Industries]

Factory yellow tab liner shims are .005. The ones we manufactured previously before switching to metal only were .0075. Allowing for diy owners to hit the nominal protrusion on the high side in an at home environment.

Please note this post is in standard American tolerances and the thread to this point is in mm.

[Parzival]

When I rebuilt my engine, the advice I got from DPI was...



Though this was with new liners from DPI. I don't know if that makes any difference.

This is very similar to the advice I got from Mike at DMC midwest, I followed this advice, and then decided to measure and got my self worked up. I have protrusion from the block and the head gasket will provide some give so it seems it would be ok...

I'm guessing your rebuild went ok? No issues?
SOMEBODY JUST HOLD ME AND TELL ME EVERYTHING IS GOING TO BE ALL RIGHT!!!

[Parzival]

Factory yellow tab liner shims are .005. The ones we manufactured previously before switching to metal only were .0075. Allowing for diy owners to hit the nominal protrusion on the high side in an at home environment.

Please note this post is in standard American tolerances and the thread to this point is in mm.

correct me if I'm wrong, In order from me to use your metal ones, I'd have to measure the protrusion with the metal shim in place, and then have the liners machined to the correct hight?
Should I stick with the yellow liner shim, or keep trying to get it dead on?

[Delorean Industries]

Just reviewed this thread and have a number of things to give input on. Please shoot over an email through our website contact page and I'll walk you through a few things to make this painless in the am with instructions.

[Parzival]

Just reviewed this thread and have a number of things to give input on. Please shoot over an email through our website contact page and I'll walk you through a few things to make this painless in the am with instructions.

Awesome, I went a head and sent tat over to you via your website!
Looking forward to hearing our input! Thank you!

[David T]

The best advice is to follow the procedure in the manual as closely as you can. Anything else could get you into trouble. Not only must you get the protrusion right, it must be right to the others on that bank. That protrusion is for the correct clamping force of the heads so the liners won't move, will seal and the coefficient of expansion is OK between the aluminum block and the steel liners. This is a big deal and close enough is not good enough. You should be measuring each part, liner, shim, and adding it all up. If you can't accurately measure nip this isn't going to work. The fact that you got it wrong indicates you need to improve your technique. If you are having too much trouble doing this with the engine in the car then maybe you should pull it. Maybe try the liner locks but don't tighten them tight, just snug enough to hold the liners in place. Problem with the liner locks is they get in the way of taking the measurements. The shims (liner base seals) are not exactly paper. The manual calls them "Excelnyl" which is probably paper treated with some kind of proprietary sealer. Once they get heated up they can't be reused. Setting liner protrusion is probably the most important step in doing the liners and heads. If, when you took it apart, you measured the shims then you would have had a good starting point at reassembly.

[Parzival]

The best advice is to follow the procedure in the manual as closely as you can. Anything else could get you into trouble. Not only must you get the protrusion right, it must be right to the others on that bank. That protrusion is for the correct clamping force of the heads so the liners won't move, will seal and the coefficient of expansion is OK between the aluminum block and the steel liners. This is a big deal and close enough is not good enough. You should be measuring each part, liner, shim, and adding it all up. If you can't accurately measure nip this isn't going to work. The fact that you got it wrong indicates you need to improve your technique. If you are having too much trouble doing this with the engine in the car then maybe you should pull it. Maybe try the liner locks but don't tighten them tight, just snug enough to hold the liners in place. Problem with the liner locks is they get in the way of taking the measurements. The shims (liner base seals) are not exactly paper. The manual calls them "Excelnyl" which is probably paper treated with some kind of proprietary sealer. Once they get heated up they can't be reused. Setting liner protrusion is probably the most important step in doing the liners and heads. If, when you took it apart, you measured the shims then you would have had a good starting point at reassembly.

Well I don't know its wrong (i've re done it sice the one was leaning over), like I said, the protrusion now is all looking like .018mm. which is within spec. These measurements were done with a straight edge and feeler gages.
Ive heard the advice a lot from people, to just use the largest size shim and skip the measuring. Well I started with that, but now am getting nervous. I want it to work and work well, so I'm sweating the details now. I've have the shop completely re building my heads, new valve guides, new freeze plugs, making sure they are perfect.

[Parzival]

So, I'll be continuing to try and get this right, it is however tough when I'm being pulled in multiple directions. Everyone has a different opinion on this stuff.
One vender says to just use the largest shim size and not worry about the measuring part (this one is shared by quite a few)

Some are of the approach that everything has to be measured down to the micron, and any deviation will result in a failure. I like measuring, and making this perfect, but to what extent.

Then there is what parts to use, I bought some head bolts from DeloreanGO and I've heard from a few people that they are wrong, and will cause the head gaskets to fail.

I'm very happy to have ALL the input, and I know that everyone is giving me their honest opinions on how to do this correctly. I just wish there was more consensus.

On one hand I know people are out there doing this with the largest shims size and skipping the measuring part, and on the other hand I know people are out there taking the precision approach. I didn't realize that opinions on this differed differed so wildly.

I'm beginning to think that taking this apart was a mistake, but what was my alternative? It has to be done.